The next generation of passenger car motor oil and heavy duty diesel engine oil categories will require equivalent antiwear properties but with lower levels of phosphorus and sulfur in the formulations in order to reduce contamination of more stringent pollution control devices. It is well known that sulfur and phosphorus containing additives impart antiwear properties to a finished oil, and also may poison or otherwise reduce the effectiveness of pollution control devices.
Zinc dialkyl dithiophosphates (“Zn DDPs”) have been used in lubricating oils for many years. Zn DDPs also have good antiwear properties and have been used to pass cam wear tests, such as the Seq IVA and TU3 Wear Test. Many patents address the manufacture and use of Zn DDPs including U.S. Pat. Nos. 4,904,401; 4,957,649; 6,114,288, all of which are incorporated herein by reference in their entirety.
Sulfur-containing antiwear are also well known and include dihydrocarbyl polysulfides; sulfurized olefins; sulfurized fatty acid esters of both natural and synthetic origins; trithiones; sulfurized thienyl derivatives; sulfurized terpenes; sulfurized polyenes; sulfurized Diels-Alder adducts, etc. Specific examples include sulfurized isobutylene, sulfurized diisobutylene, sulfurized triisobutylene, dicyclohexyl polysulfide, diphenyl polysulfide, dibenzyl polysulfide, dinonyl polysulfide, and mixtures of di-tert-butyl polysulfides such as mixtures of di-tert-butyl trisulfide, di-tert-butyl tetrasulfide and di-tert-butyl pentasulfide, among others. Of the foregoing, sulfurized olefins are used in many applications. Methods of preparing sulfurized olefins are described in U.S. Pat. Nos. 2,995,569; 3,673,090; 3,703,504; 3,703,505; 3,796,661; and 3,873,454. Also useful are the sulfurized olefin derivatives described in U.S. Pat. No. 4,654,156. Other sulfur-containing antiwear agents are described in U.S. Pat. Nos. 4,857,214, 5,242,613, and 6,096,691.
A need exists for a lubricating additive that provides excellent antiwear properties and is more compatible with pollution control devices used for automotive and diesel engines.
In view of the foregoing, exemplary embodiments disclosed herein provide a lubricated surface, a method for reducing wear between moving parts, and lubricants, and lubricant additive concentrates containing a wear reducing agent. The lubricated surface contains a base oil of lubricating viscosity, a hydrocarbon soluble titanium compound, a metal-free friction modifier, and an amount of at least one hydrocarbon soluble magnesium compound effective to provide a reduction in surface wear greater than a reduction surface wear for a lubricant composition devoid of the titanium compound, metal-free friction modifier, and magnesium compound. The lubricant composition contains no more than about 800 ppm phosphorus and is devoid of calcium detergents and organic molybdenum compounds.
In one exemplary embodiment, there is provided a vehicle having moving parts wherein the vehicle contains a lubricant for lubricating the moving parts. The lubricant is an oil of lubricating viscosity and an amount of antiwear agent providing a combination of a hydrocarbon soluble titanium compound, metal-free friction modifier, and at least one hydrocarbon soluble magnesium compound effective to provide a reduction in surface wear of the moving parts greater than a reduction surface wear of the moving parts for a lubricant composition devoid of the titanium compound, metal-free friction modifier, and magnesium compound. The lubricant composition contains no more than about 800 ppm phosphorus and is devoid of calcium detergents and organic molybdenum compounds.
In yet another embodiment there is provided a fully formulated lubricant composition include a base oil component of lubricating viscosity and an amount of antiwear agent provided by a combination of a hydrocarbon soluble titanium-containing compound, a metal-free friction modifier, and at least one hydrocarbon soluble magnesium compound effective to provide wear reduction greater than an amount of wear reduction for a lubricant composition devoid of the combination of titanium, metal-free friction modifier, and magnesium compound. The lubricant composition contains no more than about 800 ppm phosphorus and is devoid of calcium detergents and organic molybdenum compounds.
A further embodiment of the disclosure provides a lubricant additive concentrate for providing improved antiwear properties to a lubricant composition. The concentrate is substantially devoid of calcium and molybdenum and includes a hydrocarbyl carrier fluid and a synergistic amount of a combination of a hydrocarbon soluble titanium compound, a metal-free friction modifier, and a hydrocarbon soluble magnesium compound sufficient to provide from about 10 to about 500 ppm titanium and from about 120 to about 2000 ppm magnesium to a lubricant composition containing the concentrate.
As set forth briefly above, embodiments of the disclosure provide an antiwear additive including a combination of a hydrocarbon soluble titanium compound, a metal free-friction modifier, and a hydrocarbon soluble magnesium compound that may significantly improve the antiwear performance of a lubricant composition thereby enabling a decrease in the amount of phosphorus and sulfur antiwear additives required for equivalent antiwear performance. The additive may be mixed with an oleaginous fluid that is applied to a surface to reduce surface wear. In other applications, the additive may be provided in a fully formulated lubricant composition. The additive is particularly directed to meeting the currently proposed GF-4 standards for passenger car motor oils and PC-10 standards for heavy duty diesel engine oil.
The compositions and methods described herein are particularly suitable for reducing contamination of pollution control devices on motor vehicles or, in the alternative, the compositions are suitable for improving the performance of antiwear agents in lubricant formulations. Other features and advantages of the compositions and methods described herein may be evident by reference to the following detailed description which is intended to exemplify aspects of the disclosed embodiments without intending to limit the embodiments described herein.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide further explanation of the embodiments disclosed and claimed.